An early distributed radio base station system generally adopts an “RRU (Remote Radio Unit)+antenna” architecture, where the antenna is a passive unit. Generally, the “RRU+antenna” architecture is implemented in the following three forms:
1) The RRU is at the bottom of a tower, the antenna is on the tower, and the two are connected through a cable.
2) The RRU is on a tower and close to the antenna, and is mounted at the bottom or back of the antenna, and the two are connected through a cable.
3) A semi-integrated manner is adopted, where the RRU is mounted directly against the antenna and is blind-mated with the antenna or connected to the antenna through a cable.
In the semi-integrated manner of the RRU and the antenna, the RRU is generally mounted directly against the back of the antenna, where one antenna may bear one RRU or multiple RRUs. The RRU is connected to the antenna through a cable or is blind-mated with the antenna, where a waterproof design is required in both connection manners.
Later products evolve to integration of the RRU and the antenna. An antenna system integrating the RRU and a passive antenna is generally referred to as an AAS (Active Antenna System). The AAS integrates the RRU serving as an active unit and a base station antenna serving as the passive unit into one module to form a unity, thereby implementing integral installation and maintenance. Generally, a side where the RRU serving as the active unit is located is referred to as an active side, while a side where the antenna serving as the passive unit is located is referred to as an antenna side. During installation of the AAS adopting an integrated architecture, only the antenna needs to be mounted.
However, in the case of the foregoing integration manner of the RRU and the antenna, it is difficult to perform onsite replacement and maintenance and difficult to meet requirements for different product combinations.